Breaking of general rotational symmetries by multi-dimensional classical ratchets

We demonstrate that a particle driven by a set of spatially uncorrelated, independent colored noise forces in a bounded, multidimensional potential exhibits rotations that are independent of the initial conditions. We calculate the particle currents in terms of the noise statistics and the potential asymmetries by deriving an n-dimensional Fokker-Planck equation in the small correlation time limit. We analyze a variety of flow patterns for various potential structures, generating various combinations of laminar and rotational flows.Comment: Accepted, Physical Review

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Géodynamique andine : résumés étendus = Andean geodynamics : extended abstracts

Pour la première fois, la structure profonde de la Cordillère orientale des Andes centrales de l'extrême nord argentin a pu être imagée, grâce à des lignes de sismique réflection profonde obtenues par corrélation étendue de données Vibroseis standard fournies par YPF S.A. Une excellente réflectivité crustale autour de 13-15s permet d'imager un possible chevauchement au toit d'un duplex d'échelle crustale, ainsi que la rampe du mur du décollement subandin. (Résumé d'auteur

Sistema reprodutivo e polinização de Lepidagathis sessilifolia (Pohl) Kameyama ex Wassh. & J.R.I. Wood (Acanthaceae), em remanescente florestal da região sudoeste de Mato Grosso, Brasil Breeding system and pollination of Lepidagathis sessilifolia (Pohl) Kameyama Wassh ex. & J.R.I.Wood (Acanthaceae) in remnant forest in the southwest region of Mato Grosso, Brazil

O gênero Lepidagathis apresenta distribuição pantropical com cerca de 100 espécies. No Brasil ocorrem 16 espécies, a maioria nas regiões Centro - Oeste e Sudeste. O estudo foi realizado em sub - bosque de remanescente florestal do município de Tangará da Serra - MT e teve como objetivo analisar a fenologia de floração, descrever a morfologia e biologia floral, verificar os visitantes florais e avaliar o sistema e o sucesso reprodutivo por meio de polinizações manuais. Lepidagathis sessilifolia apresenta inflorescências espiciformes, terminais, com cálice de cor rósea vistosa e corola de coloração branco-rósea. A floração ficou restrita aos meses de março a abril, durante a estação chuvosa. A senescência floral ocorreu após 24 ou 48 horas. A viabilidade dos grãos de pólen foi elevada (92,5%). O único polinizador observado visitando as flores de L. sessilifolia foi a abelha Partamona nhambiquara (Apidae - Meliponini). O sistema reprodutivo misto da espécie é caracterizado pela formação de frutos por meio de agamospermia, autopolinização e polinização cruzada. Esse sistema reprodutivo flexível é vantajoso, pois, garante a manutenção da espécie na área de estudo mesmo na ausência de polinizadores.<br>The genus Lepidagathis has pantropical distribution and about 100 species, 16 occurring in Brazil, mostly in the Midwest and Southeast regions. The research was carried out to evaluate in the understory of a forest remnant in Tangará da Serra County - MT to examine the flowering phenology, describe the floral morphology and biology and verify the floral visitors to evaluate the system and reproductive success through hand pollination tests. Lepidagathis sessilifolia shows spiciform and terminal inflorescence with calyx of pink color and corolla whitish-pink. Flowering was restricted from March to April, during the rainy season. Floral senescence occurred after 24 or 48 hours. The viability of pollen grains was high (92.5%). The effective pollinator of L. sessilifolia was Partamona nhambiquara (Apidae - Meliponini). The mixed mating system of the species is characterized by the formation of fruits by agamospermy, self and cross-pollination, spontaneous self-pollination, agamospermy and outcrossing. This flexible reproductive system is advantageous because it ensures the maintenance of species in the study area even in the absence of pollinators

Testing reproducibility of vitrinite and solid bitumen reflectance measurements in North American unconventional source-rock reservoir petroleum systems

An interlaboratory study (ILS) was conducted to test reproducibility of vitrinite and solid bitumen reflectance measurements in six mudrock samples from United States unconventional source-rock reservoir petroleum systems. Samples selected from the Marcellus, Haynesville, Eagle Ford, Barnett, Bakken and Woodford are representative of resource plays currently under exploitation in North America. All samples are from marine depositional environments, are thermally mature (T >445 °C) and have moderate to high organic matter content (2.9–11.6 wt% TOC). Their organic matter is dominated by solid bitumen, which contains intraparticle nano-porosity. Visual evaluation of organic nano-porosity (pore sizes 1.0 produced lowest R values, generally ≤0.5% (absolute reflectance), similar to a prior ILS for similar samples. Other traditional approaches to outlier removal (outside mean ± 1.5*interquartile range and outside F10 to F90 percentile range) also produced similar R values. Standard deviation values < 0.15*(VR or BR) reduce R and should be a requirement of dispersed organic matter reflectance analysis. After outlier removal, R values were 0.1%–0.2% for peak oil thermal maturity, about 0.3% for wet gas/condensate maturity and 0.4%–0.5% for dry gas maturity. That is, these R values represent the uncertainty (in absolute reflectance) that users of vitrinite and solid bitumen reflectance data should assign to any one individual reported mean reflectance value from a similar thermal maturity mudrock sample. R values of this magnitude indicate a need for further standardization of reflectance measurement of dispersed organic matter. Furthermore, these R values quantify realistic interlaboratory measurement dispersion for a difficult but critically important analytical technique necessary for thermal maturity determination in the source-rock reservoirs of unconventional petroleum systems.This research was funded by the USGS Energy Resources Program

Fenologia reprodutiva e sistema de polinização de Ziziphus joazeiro Mart. (Rhamnaceae): atuação de Apis mellifera e de visitantes florais autóctones como polinizadores Reproductive phenology and pollination system of Ziziphus joazeiro Mart. (Rhamnaceae): the role of Apis mellifera and autochthonous floral visitors as pollinators

(Fenologia reprodutiva e sistema de polinização de Ziziphus joazeiro Mart. (Rhamnaceae): atuação de Apis mellifera e de visitantes florais autóctones como polinizadores). Ziziphus joazeiro é uma espécie endêmica da Caatinga, com grande utilidade econômica, cuja biologia reprodutiva é pouco conhecida. Este estudo aborda a fenologia reprodutiva, a biologia floral e o sistema de polinização de Ziziphus joazeiro no Cariri Paraibano, Nordeste do Brasil. Os períodos de floração e de frutificação ocorreram no fim da estação seca e início da chuvosa, com picos nos meses de dezembro (floração) e fevereiro (frutificação). As flores são do tipo disco, esverdeadas, duram cerca de 12 horas e possuem disco nectarífero largo e amarelo, o qual circunda o gineceu. Ocorre protandria associada a outro tipo de dicogamia, a heterodicogamia. Ziziphus joazeiro produz néctar em pequena quantidade (1 µl), com alta concentração de açúcares (75%). Os visitantes florais observados foram vespas, abelhas e moscas. Apis mellifera apresentou maior freqüência de visitas (77,5%), seguida pelo grupo das vespas (20,4%), ambos considerados polinizadores efetivos. As moscas e as outras espécies de abelhas apresentaram baixo percentual de visitas (2,1%) e foram consideradas pilhadoras de néctar. A elevada taxa de desenvolvimento inicial de frutos por inflorescência pode sugerir alta eficiência dos polinizadores, uma vez que o mecanismo de dicogamia presente na espécie praticamente impede a ocorrência de autopolinização espontânea e de geitonogamia.<br>(Reproductive phenology and pollination system of Ziziphus joazeiro Mart. (Rhamnaceae): the role of Apis mellifera and autochthonous floral visitors as pollinators). Ziziphus joazeiro is an endemic species of the Caatinga with great economic importance, whose reproductive biology is poorly understood. This paper analyses the reproductive phenology, floral biology and pollination system of Ziziphus joazeiro at Cariri Paraibano, northeastern Brazil. Flowering and fruiting periods occurred at the end of the dry season and beginning of the rainy season, with peaks in December (flowering) and February (fruiting). The green, dish-shaped flowers last about 12 hours and have a large yellow nectary surrounding the gynoecium. Protandry occurs associated with heterodichogamy, another type of dichogamy. Ziziphus joazeiro produces little nectar (1 µl) but with a high sugar concentration (75%). Floral visitors were wasps, bees and flies. Apis mellifera had the highest frequency of visits (77.5%), followed by wasps (20.4%), both acting as effective pollinators. Flies and other bee species had a lower percentage of visits (2.1%) and acted as nectar robbers. The high rate of initial fruit development per inflorescence suggests high pollinator efficiency, since the dichogamic mechanism prevents the occurrence of spontaneous self-pollination and geitonogamy